/**
 * 第i天身高增加2^i，问第几天超过H
 */
#include <bits/stdc++.h>
using namespace std;

#include <bits/extc++.h>

using llt = long long;
using vi = vector<int>;
using pii = pair<int, int>;
using vpii = vector<pii>;
using vll = vector<llt>;

template<typename T>
void input(vector<T> & a, int n){
    a.assign(n + 1, {});
    for(int i=1;i<=n;++i) cin >> a[i];
    return;
}

template<typename T>
istream & operator >> (istream & is, vector<T> & v){
    for(auto & i : v) is >> i;
    return is;
}

llt H;

void work(){
    cin >> H;
    int k = 1;
    llt s = 1;
    llt c = 1;
    while(1){
        if(s > H) break;
        c <<= 1;
        s += c;
        k += 1;
    }
    cout << k << endl;
    return;
}

int main(){
#ifndef ONLINE_JUDGE
    freopen("z.txt", "r", stdin);
#endif
    ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
    int nofkase = 1;
    // cin >> nofkase;

    while(nofkase--) work();
    return 0;
}